1. Field of Invention
The invention relates to a sealed air purifier that can greatly prevent infections. It is characterized in that:                1. The interior of the disclosed sealed air purifier is completely sealed when it is not in use. Therefore, viruses filtered out by the super ULPA filter do not spread all over with air. The infection rate can thus be largely reduced.        2. The super ULPA filter and the sterilizing device that need to be replaced periodically are disposed in a disposable second shell. When replacing the second shell, it is completely isolated from the environment as a sealed filter system. Therefore, the safety of the person who replaces the second shell can be guaranteed.        
2. Related Art
Since the outbreak of SARS and H1N1, wearing a mask in the public area has become a popular practice for most people. However, all but N95 masks cannot filter viruses of size smaller than 0.5 um at the 95% level. So most of the masks are not so effective in preventing infections. However, there are relatively few N95 masks. The filtered viruses also stay thereon. That is, the viruses filtered by the N95 mask may still propagate via air. So there is still contamination.
The common air purifier uses a fan to circulate air and force it to be filtered. Even if a high-efficiency HEPA filter is used to capture viruses larger than 0.3 um, the viruses filtered out by it are not restricted in a sealed space. They can still spread into space. This is one of its drawbacks. Moreover, there is a huge risk for a person to make periodic replacements of the HEPA filter. Since the HEPA filter is not completely sealed and isolated, the person may be infected during the replacement. This is its second shortcoming.
In view of the foregoing, the invention provides an entirely new sealed air purifier to resolve the above-mentioned problems.